Messages in this thread | | | Date | Mon, 18 Jul 2022 10:35:55 +0200 | Subject | Re: [PATCH v3 net-next 2/3] net: ipv6: new accept_untracked_na option to accept na only if in-network | From | Nicolas Dichtel <> |
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Le 14/07/2022 à 01:40, Jaehee Park a écrit : > This patch adds a third knob, '2', which extends the > accept_untracked_na option to learn a neighbor only if the src ip is > in the same subnet as an address configured on the interface that > received the neighbor advertisement. This is similar to the arp_accept > configuration for ipv4. > > Signed-off-by: Jaehee Park <jhpark1013@gmail.com> > Suggested-by: Roopa Prabhu <roopa@nvidia.com> > --- > Documentation/networking/ip-sysctl.rst | 51 +++++++++++++++----------- > net/ipv6/addrconf.c | 2 +- > net/ipv6/ndisc.c | 29 ++++++++++++--- > 3 files changed, 55 insertions(+), 27 deletions(-) > > diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst > index 5c017fc1e24d..722ec4f491db 100644 > --- a/Documentation/networking/ip-sysctl.rst > +++ b/Documentation/networking/ip-sysctl.rst > @@ -2483,27 +2483,36 @@ drop_unsolicited_na - BOOLEAN > > By default this is turned off. > > -accept_untracked_na - BOOLEAN > - Add a new neighbour cache entry in STALE state for routers on receiving a > - neighbour advertisement (either solicited or unsolicited) with target > - link-layer address option specified if no neighbour entry is already > - present for the advertised IPv6 address. Without this knob, NAs received > - for untracked addresses (absent in neighbour cache) are silently ignored. > - > - This is as per router-side behaviour documented in RFC9131. > - > - This has lower precedence than drop_unsolicited_na. > - > - This will optimize the return path for the initial off-link communication > - that is initiated by a directly connected host, by ensuring that > - the first-hop router which turns on this setting doesn't have to > - buffer the initial return packets to do neighbour-solicitation. > - The prerequisite is that the host is configured to send > - unsolicited neighbour advertisements on interface bringup. > - This setting should be used in conjunction with the ndisc_notify setting > - on the host to satisfy this prerequisite. > - > - By default this is turned off. > +accept_untracked_na - INTEGER > + Define behavior for accepting neighbor advertisements from devices that > + are absent in the neighbor cache: > + > + - 0 - (default) Do not accept unsolicited and untracked neighbor > + advertisements. > + > + - 1 - Add a new neighbor cache entry in STALE state for routers on > + receiving a neighbor advertisement (either solicited or unsolicited) > + with target link-layer address option specified if no neighbor entry > + is already present for the advertised IPv6 address. Without this knob, > + NAs received for untracked addresses (absent in neighbor cache) are > + silently ignored. > + > + This is as per router-side behavior documented in RFC9131. > + > + This has lower precedence than drop_unsolicited_na. > + > + This will optimize the return path for the initial off-link > + communication that is initiated by a directly connected host, by > + ensuring that the first-hop router which turns on this setting doesn't > + have to buffer the initial return packets to do neighbor-solicitation. > + The prerequisite is that the host is configured to send unsolicited > + neighbor advertisements on interface bringup. This setting should be > + used in conjunction with the ndisc_notify setting on the host to > + satisfy this prerequisite. > + > + - 2 - Extend option (1) to add a new neighbor cache entry only if the > + source IP address is in the same subnet as an address configured on > + the interface that received the neighbor advertisement. > > enhanced_dad - BOOLEAN > Include a nonce option in the IPv6 neighbor solicitation messages used for > diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c > index 88becb037eb6..6ed807b6c647 100644 > --- a/net/ipv6/addrconf.c > +++ b/net/ipv6/addrconf.c > @@ -7042,7 +7042,7 @@ static const struct ctl_table addrconf_sysctl[] = { > .data = &ipv6_devconf.accept_untracked_na, > .maxlen = sizeof(int), > .mode = 0644, > - .proc_handler = proc_dointvec_minmax, > + .proc_handler = proc_dointvec, > .extra1 = (void *)SYSCTL_ZERO, > .extra2 = (void *)SYSCTL_ONE, Maybe keeping proc_dointvec_minmax with SYSCTL_TWO for extra2 is better to avoid accepting all values. It enables to add another value later.
Regards, Nicolas
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